Herbicidal composition and a method to control undesired vegetation

ABSTRACT

This invention is related to herbicidal compositions comprising derivatives of benzenesulfonylurea and 2-methoxy-3,6-dichlorobenzoic acid for control of undesired vegetation by treating said vegetation and locus to be protected by said compositions. 
     To eliminate the detrimental effects on crop rotation by lowering dosage of herbicide and to widen its activity spectrum a herbicidal composition is proposed comprising a mixture of ammonium salts of benzenesulfonylurea derivatives and of 2-methoxy-3,6-dichlorobenzoic acid with additives. 
     The treatment of the vegetation and locus is performed by water solution of the disclosed composition with the dosage in the range of 50-500 g/ha of composition.

This application is a 371 of PCT/RU93/00211, filed Sep. 2, 1993.

FIELD OF UTILITY

The instant application is related to agriculture, specifically to chemical agents for plant protection and eradication of undesired vegetation.

BACKGROUND OF THE INVENTION

Derivatives of sulfonylurea of general formula ##STR1## wherein R₁ =Cl, COOCH₃, OCH₂ CH₂ Cl and R₂ =H, CH₃ are known as herbicides for control of weeds in cereals 1!.

All herbicides of the sulfonylurea series have considerable advantage compared to other herbicides because of the low dosage (8-50 g/ha of active principle) and high selectivity, although their low degradation rate in soil causes detrimental effects in crop rotation as well as resistance in a number of weeds. Accidental over-dosage of these herbicides can result in serious phytotoxicity for certain cereals.

All known herbicidal compositions based on sulfonylurea are wettable powders or microgranules. The absence of water-soluble preparations in these series is explainable by low water-solubility of sulfonylurea and their relatively high hydrolysis rate.

The use of 2-methoxy-3,6-dichlorobenzoic acid and its salts as herbicides to control weeds in cereals by application of 150 g/ha of the active principle is known (preparation Banvel-D or Dicamba) 2! The advantage of this herbicide is the complete absence of resistance to it in weeds. Nevertheless the relatively high dosage of the preparation and rather narrow spectrum of activity is a disadvantage.

Increasing of the herbicidal activity of 2-methoxy-3,6-dichlorobenzoic acid and lowering its dosage as well as elimination of disadvantages inherent to known herbicides of benzenesulfonylurea series poses a problem of creation of herbicidal composition with low dosage and wide activity spectrum, absence of detrimental effects on crop rotation and phytotoxicity in crops to be protected, and not leading to development of resistance in weeds.

The most advantageous solution of this problem is a composition for control of undesired vegetation comprising a mixture based on benzenesulfonylurea derivative ##STR2## and 2-methoxy-3,6-dichlorobenzoic acid with the addition of surfactant, organic solvent and water 3!.

A method for control of undesired vegetation in cereals is known. It comprises the application of emulsion or suspension of the aforementioned herbicidal composition on basis of benzenesulfonylurea derivative and 2-methoxy-3,6-dichlorobenzoic acid with addition of a surfactant, organic solvent and water. The application dosage to weeds is 3 kg/ha. No exact examples describing the components of the composition and method of its application are disclosed.

DETAILED DESCRIPTION OF THE INVENTION

The instant invention discloses a herbicidal composition for use in cereals, comprising ammonium salts of benzenesulfonylureas of general formula (I) ##STR3## wherein: R₁ =Cl, COOCH₃ or OCH₂ CH₂ Cl;

R₂ =H or CH₃ ;

R₃ =CH₃ or N(CH₃)₂ ;

R₄ =OCH₃ or ON═C(CH₃)₂ ;

R₅ =CH₃ or C₂ H₅ ;

R₆ =C₂ H₅ or CH₂ CH₂ OH,

together with ammonium salt of 2-methoxy-3,6-dichlorobenzoic acid of general formula (II) ##STR4## wherein: R₇ =CH₃ or C₂ H₅ ;

R₈ =H, CH₃ or CH₂ CH₂ OH;

R₉ =H, C₂ H₅ or CH₂ CH₂ OH

a surfactant, an organic solvent and water with the following weight percentage of components:

    ______________________________________                                         ammonium salt of benzenesulfonylurea derivative                                                           2,0-50                                              ammonium salt of 2-methoxy-3,6-dichlorobenzoic acid                                                       5,0-50                                              surfactant                 1,0-5,0                                             organic solvent             10-40                                              water                      up to 100.                                          ______________________________________                                    

As surfactants the following agents are applicable: bis-polyoxyethylated alkylamine, sodium bis(2-ethylhexyl)succinate sulfonate, polyethyleneglycol monoalkyl ethers or alkylaryl ethers of polyethyleneglycol or polypropyleneglycol.

Triethyleneglycol is used as organic solvent. A method for control of undesired vegetation in cereals comprises applying to the locus to be protected a herbicidal composition based on derivative of benzenesulfonylurea, 2-methoxy-3,6-dichlorobenzoic acid with addition of surfactant, organic solvent and water is characterized in that benzenesulfonylurea derivative and 2-methoxy-3,6-dichlorobenzoic acid are employed in the form of their ammonium salts with the respective general formulas (I) and (II) ##STR5## wherein: R₁ =Cl, CCOCH₃ or OCH₂ CH₂ Cl;

R₂ =H or CH₃ ;

R₃ =CH₃ or N(CH₃)₂ ;

R₄ =OCH₃ or ON═C(CH₃)₂ ;

R₅ =CH₃ or C₂ H₅ ;

R₆ =C₂ H₅ or CH₂ CH₂ OH, and ##STR6## wherein: R₇ =CH₃ or C₂ H₅ ;

R₈ =H, CH₃ or CH₂ CH₂ OH;

R₉ =H, C₂ H₅ or CH₂ CH₂ OH

with the following weight percentage of components:

    ______________________________________                                         ammonium salt of benzenesulfonylurea derivative                                                           2,0-50                                              ammonium salt of 2-methoxy-3,6-dichlorobenzoic acid                                                       5,0-50                                              surfactant                 1,0-5,0                                             organic solvent             10-40                                              water                      up to 100.                                          ______________________________________                                    

The dosage of active principles is 25-125 g/ha.

The invention is further illustrated by the following examples.

EXAMPLE 1 Diethylethanolammonium salt of 1-(2-chlorobenzenesulfonyl)-3-(4-methyl-6-methoxy-1,3,5-triazin-2-yl)urea

The reaction vessel was charged with 357 g (1 Mole) of 1-(2-chlorobenzene sulfonyl)-3-(4-methyl-6-methoxy-1,3,5-triazin-2-yl)urea, 117 g (1 Mole) or diethylaminoethanol and 10 L of water and the suspension was stirred at room temperature until solution was complete. The solvent was evaporated on rotary vacuum evaporator and the product collected in quantitative yield.

Elemental analyses and physico-chemical data for the ammonium salts of the sulfonylureas, prepared by the method described in Example 1 are presented in Table 1.

EXAMPLE 2 Diethylethanolammonium salt of 2-methoxy-3,6-dichlorobenzoic acid

The reaction vessel was charged with 221 g (1 Mole) of 2-methoxy-3,6-dichlorobenzoic acid, 117 g (1 Mole) of diethylaminoethanol and 2 L of water and the suspension stirred at 50° C. until solution was complete. The solvent was evaporated on rotary vacuum evaporator and the product collected in quantitative yield.

By the method described in Example 2 dimethylammonium and ethyldiethanolammonium salts were prepared. Elemental analyses for the salts are presented in Table 2.

EXAMPLE 3 Herbicidal Composition

The reaction vessel was charged with calculated amounts of the ammonium salt of benzenesulfonylurea (I) and calculated amounts of the ammonium salt of 2-methoxy-3,6-dichlorobenzoic acid (II), the quantity of the latter depending on the chosen ratio of the two components (mass ratio from 10:1 to 1:25). The necessary quantity of surfactant, triethyleneglycol and water was added and the mixture was stirred at room temperature till the solution was completed.

Examples of herbicidal compositions with different ratios of constituents are presented in Table 3.

EXAMPLE 4 Laboratory Testing of Herbicidal Compositions (Examples 1.1, 1.2 and 1.3)

Herbicidal compositions with different ratios of ammonium salts of benzenesulfonylureas (I) and 2-methoxy-3,6-dichlorobenzoic acid (II) were tested in greenhouse. In vegetation experiments for crops and weeds the following species were used: wheat, corn, lambsquarters, corn grass, ryegrass, sortell, pigweed and corn poppy. The treatment of growing plants was performed for cereals at the third leaf phase, for other species--at the appearance of the second true leaf phase. The dosage of the herbicidal composition was 100 g/ha. The humidity of soil was kept at 60-70% of saturation by daily watering. The effectiveness of herbicidal compositions was evaluated on the 14th day after spray application. The results obtained show a considerable synergism of combined application of herbicides (I) and (II). The results are presented in Tables 4-7.

EXAMPLE 5 Field Tests on Wheat

Area under spring wheat (Moskovskaya 35) was weeded mainly with lambsquarters, hemp nettle, scentless chamomile, catchweed bedstraw, sow thistle and chickweed. The herbicidal compositions were applied at the bushing stage of crop in dosage 500 L/ha of their water solution.

The field tests confirmed the substantial synergism of components in the herbicidal composition.

Results presented in Tables 8-9 show that application of the mixture of herbicides effectively protects crops like wheat at substantially lower dosage thus making the mixed preparation safe for crop rotation. The use of herbicidal compositions of the instant invention permits the lowering the dosage of salt of benzenesulfonylurea derivative (I) from 2 to 5 times and dosage of 2-methoxy-3,6-dichlorobenzoic acid salt (II)--3 times in comparison with the application of individual chemicals and increases their effectiveness.

EXAMPLE 6 Field Tests on Corn

Tests were performed on area under corn (hybrid POCC-144). Herbicidal compositions were applied as water solutions at 3-5 leaf phase of corn. The main weeds were millet species--48-77% and dicotyledonous--33-52%. The percentage of barnyard grass in millet species was 32-59%. 85-96% of the dicotyledonous consisted of pigweed. The results presented in Table 7 show that the herbicidal composition of the instant invention effectively controls dicotyledonous weeds and effects a considerable phytotoxicity towards monocotyledonous weeds. The application of mixed herbicidal comsitions based on derivative of benzenesulfonylurea (IB) and 2-methoxy-3,6-dichlorobenzoic acid (II) results in lowering dosage of (IB) 1.5 times and (II) 2-8 times, substantially increasing the effectiveness of preparations for weed control.

The herbicidal compositions of the instant invention displayed special effectiveness in control of undesired vegetation in areas under grain cereals and corn.

Related Information

1! C. Smith, Sulfonylurea herbicides, 1991, PJB Publication Ltd., p. 51, 67, 99, 107

2! N. N. Mel'nikov, K. V. Novozhilov, T. M. Ryzhkova, Khimicheskie sredstva zashchity rastenil', 1980, "Khimiya", Moscow, p. 27

3! EP application #9236273

                                      TABLE 1                                      __________________________________________________________________________     HERBICIDAL COMPOSITION      Percentage of components  weight %!                Variants                    a   b  c  d  e                                     1                           2   3  4  5  6                                     __________________________________________________________________________     1.1                                                                              Diethylethanolammonium salt                                                                              2    4  2 10 10                                      (IA) R.sub.1 = Cl; R.sub.2 = H, R.sub.3 = CH.sub.3, R.sub.4 = OCH.sub.3        Dimethylammonium sait (II)                                                                               50  40 40 10 50                                      Surfactant                1    2  3  2  5                                      Triethyleneglycol         17  20 20 35 10                                      Water                     30  34 35 43 25                                    1.2                                                                              Diethylethanolammonium salt                                                                              2.5 25 25 25 50                                      (IB) R.sub.1 = Cl, R.sub.2 = H, R.sub.3 = N(CH.sub.3).sub.2, R.sub.4 =         --ON═C(CH.sub.3).sub.2                                                     Dimethylammonium salt (II)                                                                               5   10 15 25 25                                      Surfactant                2.5  2  2  2  4                                      Triethyleneglycol         30  23 23 13 11                                      Water                     60  40 35 35 10                                    1.3                                                                              Diethylethanolammonium salt                                                                              1    1  3  7  7                                      (IA) R.sub.1 = Cl, R.sub.2 = H, R.sub.3 = CH.sub.3, R.sub.4 = OCH.sub.3        Diethylethanolammonium salt                                                                              2    2  6 14 14                                      (IB) R.sub.1 = Cl, R.sub.2 = H, R.sub.3 = N(CH.sub.3).sub.2, R.sub.4 =         --ON═C(CH.sub.3).sub.2                                                     Dimethylammonium salt (II)                                                                               10  50 30 10 50                                      Diethylaminoethanol       5    3  4  5  2                                      Triethyleneglycol         32  14 17 24  7                                      Water                     50  30 40 40 20                                    1.4                                                                              Ethyldiethanolammonium salt                                                                              2    2                                               (IC) R.sub.1 = COOCH.sub.3, R.sub.2 = H, R.sub.3 = CH.sub.3, R.sub.4 =         OCH.sub.3                                                                      Ethyldiethanolammonium salt (II)                                                                         40  40                                               Surfactant                3    2                                               Triethyleneglycol         15  31                                               Water                     40  25                                             1.5                                                                              Ethyldiethanolammonium salt                                                                              2    4                                               (ID) R.sub.1 = OCH.sub.2 CH.sub.2 Cl, R.sub.2 = H, R.sub.3 = CH.sub.3,         R.sub.4 = OCH.sub.3                                                            Ethyldiethanolammonium salt (II)                                                                         40  40                                               Surfactant                3    2                                               Triethyleneglycol         15  14                                               Water                     40  40                                             1.6                                                                              Ethyldiethanolammonium salt                                                                              2    8                                               (IC) R.sub.1 = COOCH.sub.3, R.sub.2 = H, R.sub.3 = CH.sub.3, R.sub.4 =         OCH.sub.3                                                                      Ethyldiethanolammonium salt (II)                                                                         40  40                                               Surfactant                3    2                                               Triethyleneglycol         25  25                                               Water                     30  25                                             1.7                                                                              Diethylethanolammonium salt    2  3  5  8                                      (IA) R.sub.1 = Cl, R.sub.2 = H, R.sub.3 = CH.sub.3, R.sub.4 = OCH.sub.3        Diethylethanolammonium salt (II)                                                                             50 45 50 48                                      Tenside                        3  2  2  2                                      Triethyleneglycol             20 25 25 20                                      Water                         25 25 18 22                                    1.8                                                                              Diethylethanolammonium salt                                                                              2    4  6  8 10                                      (IG) R.sub.1 = Cl, R.sub.2 = CH.sub.3, R.sub.3 = CH.sub.3,                     R.sub.4 = OCH.sub.3                                                            Diethylethanolammonium salt (II)                                                                         50  40 42 48 50                                      Tenside                   2    2  2  3  3                                      Triethyleneglycol         20  24 25 21 17                                      Water                     26  30 25 20 20                                    1.9                                                                              Diethylethanolammonium salt                                                                              4   10                                               (IF) R.sub.1 = COOCH.sub.3, R.sub.2 = CH.sub.3, R.sub.3 = CH.sub.3,            R.sub.4 = OCH.sub.3                                                            Diethylethanolammonium salt (II)                                                                         40  50                                               Tenside                   3    2                                               Triethyleneglycol         25  18                                               Water                     28  20                                             __________________________________________________________________________

                                      TABLE 2                                      __________________________________________________________________________                                    Summary                                         # R.sub.1                                                                              R.sub.2                                                                           R.sub.3                                                                             R.sub.4                                                                              R.sub.5                                                                           R.sub.6                                                                              formula                                         __________________________________________________________________________      1.                                                                              Cl    H  CH.sub.3                                                                            OCH.sub.3                                                                            CH.sub.3                                                                          CH.sub.3                                                                             C.sub.16 H.sub.23 ClN.sub.6 O.sub.5 S            2.                                                                              Cl    H  CH.sub.3                                                                            OCH.sub.3                                                                            C.sub.2 H.sub.5                                                                   C.sub.2 H.sub.5                                                                      C.sub.18 H.sub.27 ClN.sub.6 O.sub.5 S            3.                                                                              Cl    H  CH.sub.3                                                                            OCH.sub.3                                                                            C.sub.2 H.sub.5                                                                   CH.sub.2 CH.sub.2 OH                                                                 C.sub.18 H.sub.27 ClN.sub.6 O.sub.6 S            4.                                                                              Cl    CH CH.sub.3                                                                            OCH.sub.3                                                                            C.sub.2 H.sub.5                                                                   C.sub.2 H.sub.5                                                                      C.sub.19 H.sub.29 ClN.sub.6 O.sub.5 S            5.                                                                              Cl    CH.sub.3                                                                          CH.sub.3                                                                            OCH.sub.3                                                                            C.sub.2 H.sub.5                                                                   CH.sub.2 CH.sub.2 OH                                                                 C.sub.19 H.sub.29 ClN.sub.6 O.sub.6 S            6.                                                                              Cl    H  N(CH.sub.3).sub.2                                                                   ONC(CH.sub.3).sub.2                                                                  C.sub.2 H.sub.5                                                                   C.sub.2 H.sub.5                                                                      C.sub.21 H.sub.33 ClN.sub.8 O.sub.5 S            7.                                                                              COOCH.sub.3                                                                          H  CH.sub.3                                                                            OCH.sub.3                                                                            CH.sub.3                                                                          CH.sub.3                                                                             C.sub.18 H.sub.26 N.sub.6 O.sub.7 S              8.                                                                              COOCH.sub.3                                                                          H  CH.sub.3                                                                            OCH.sub.3                                                                            C.sub.2 H.sub.5                                                                   C.sub.2 H.sub.5                                                                      C.sub.20 H.sub.30 N.sub.6 O.sub.7 S              9.                                                                              COOCH.sub.3                                                                          H  CH.sub.3                                                                            OCH.sub.3                                                                            C.sub.2 H.sub.5                                                                   CH.sub.2 CH.sub.2 OH                                                                 C.sub.20 H.sub.30 N.sub.6 O.sub.8 S             10.                                                                              COOCH.sub.3                                                                          CH.sub.3                                                                          CH.sub.3                                                                            OCH.sub.3                                                                            C.sub.2 H.sub.5                                                                   C.sub.2 H.sub.5                                                                      C.sub.21 H.sub.32 N.sub.6 O.sub.7 S               COOCH.sub.3                                                                          CH.sub.3                                                                          CH.sub.3                                                                            OCH.sub.3                                                                            C.sub.2 H.sub.5                                                                   CH.sub.2 CH.sub.2 OH                                                                 C.sub.21 H.sub.32 N.sub.6 O.sub.8 S               OCH.sub.2 CH.sub.2 Cl                                                                H  CH.sub.3                                                                            OCH.sub.3                                                                            C.sub.2 H.sub.5                                                                   C.sub.2 H.sub.5                                                                      C.sub.21 H.sub.31 ClN.sub.6 O.sub.6 S             OCH.sub.2 CH.sub.2 Cl                                                                H  CH.sub.3                                                                            OCH.sub.3                                                                            C.sub.2 H.sub.5                                                                   CH.sub.2 CH.sub.2 OH                                                                 C.sub.20 H.sub.31 ClN.sub.6 O.sub.7             __________________________________________________________________________                                    S                                                                                Hydrolysis                                    Elemental analyses                                                                            M.p.                                                                               CO cm.sup.-1                                                                          nm     20° C.                                 calcul. %  found %                                                                            °C.                                                                         mol.                                                                               ion                                                                               mol. ion                                                                              0.5 days                                      __________________________________________________________________________     1. C 43.0                                                                              42.7                                                                               42.9                                                                              154-6                                                                              1722                                                                               1658                                                                              219 231                                                                               3416                                             H 5.2                                                                               5.3 5.5                                                                   N 18.8                                                                              18.2                                                                               18.7                                                               2. C 45.6                                                                              45.7                                                                               45.6                                                                              142-6                                                                              1730                                                                               1651                                                                              220 234                                                                               3530                                             H 5.7                                                                               5.5 5.6                                                                   N 17.7                                                                              17.9                                                                               18.0                                                               3. C 44.1                                                                              43.9                                                                               43.0                                                                              142-4                                                                              1725                                                                               1655                                                                              221 233                                                                               3249                                             H 5.5                                                                               5.3 5.4                                                                   N 17.1                                                                              17.2                                                                               17.1                                                               4. C 46.7                                                                              46.5                                                                               46.6                                                                              124-8                                                                              1723                                                                               1652                                                                              220 235                                                                                979                                             H 5.9                                                                               5.8 5.9                                                                   N 17.2                                                                              17.0                                                                               16.9                                                               5. C 45.2                                                                              45.4                                                                               45.3                                                                              116-9                                                                              1721                                                                               1648                                                                              223 233                                                                                895                                             H 5.8                                                                               5.8 5.9                                                                   N 16.7                                                                              16.5                                                                               16.8                                                               6. C 46.3                                                                              46.5                                                                               46.4                                                                              125-7                                                                              1720                                                                               1650                                                                              225 240                                                                                738                                             H 6.1                                                                               6.1 6.0                                                                   N 20.6                                                                              20.7                                                                               20.6                                                               7. C 46.0                                                                              45.8                                                                               46.1                                                                              141-4                                                                              1718                                                                               1648                                                                              222 235                                                                               2174                                             H 5.5                                                                               5.6 5.5                                                                   N 17.9                                                                              17.8                                                                               17.7                                                               8. C 48.2                                                                              48.3                                                                               48.4                                                                              123-5                                                                              1716                                                                               1642                                                                              224 233                                                                               2196                                             H 6.0                                                                               6.1 5.9                                                                   N 19.9                                                                              16.7                                                                               16.6                                                               9. C 46.7                                                                              46.8                                                                               46.7                                                                              107-9                                                                              1721                                                                               1650                                                                              222 237                                                                               1837                                             H 5.8                                                                               5.7 5.7                                                                   N 16.3                                                                              16.2                                                                               16.2                                                               1O.                                                                               C 49.2                                                                              49.1                                                                               49.3                                                                              121-4                                                                              1713                                                                               1645                                                                              225 241                                                                                884                                             H 6.3                                                                               6.2 6.1                                                                   N 16.4                                                                              16.4                                                                               16.2                                                                  C 47.7                                                                              47.9                                                                               47.8                                                                              112-6                                                                              1721                                                                               1652                                                                              221 234                                                                                796                                             H 6.1                                                                               6.0 5.9                                                                   N 15.9                                                                              16.1                                                                               16.2                                                                  C 46.3                                                                              46.5                                                                               46.4                                                                              154-8                                                                              1726                                                                               1655                                                                              224 238                                                                               3845                                             H 6.0                                                                               6.1 5.9                                                                   N 16.2                                                                              16.0                                                                               16.3                                                                  C 44.9                                                                              45.1                                                                               45.0                                                                              144-8                                                                              1718                                                                               1642                                                                              221 234                                                                               3718                                             H 5.8                                                                               5.9 5.8                                                                   N 15.7                                                                              15.5                                                                               15.8                                                               __________________________________________________________________________

                                      TABLE 3                                      __________________________________________________________________________                       Summary                                                                               Elemental analyses                                    R.sub.7                                                                              R.sub.8                                                                              R.sub.9                                                                              formula                                                                               % calc.  % found                                      __________________________________________________________________________     1. C.sub.2 H.sub.5                                                                   C.sub.2 H.sub.5                                                                      CH.sub.2 CH.sub.2 OH                                                                 C.sub.14 H.sub.21 Cl.sub.2 NO.sub.4                                                   C  49.7                                                                              49.7                                                                              49.8                                                                  H  6.2                                                                               6.3                                                                               6.1                                                                   N  4.1                                                                               4.0                                                                               4.2                                                                   Cl 21.0                                                                              21.3                                                                              21.2                                         2. C.sub.2 H.sub.5                                                                   CH.sub.2 CH.sub.2 OH                                                                 CH.sub.2 CH.sub.2 OH                                                                 C.sub.14 H.sub.21 ClNO.sub.5                                                          C  47.4                                                                              47.3                                                                              47.4                                                                  H  5.9                                                                               5.9                                                                               6.0                                                                   N  3.9                                                                               3.7                                                                               3.8                                                                   Cl 20.0                                                                              19.9                                                                              19.8                                         __________________________________________________________________________

                  TABLE 4                                                          ______________________________________                                         Herbicidal action of composition 1.1                                           Plant mass in % of controls (+ denotes increase over controls)                 II\IA                                                                        0     2         4    6      8    10                                    ______________________________________                                         Wheat                                                                           0     0      0         0    0      0    0                                     10     0      0         0    0      0    0                                     20     0      0         0    0      0    0                                     30     0      0         0    0      0    0                                     40     0      0         0    0      0    0                                     50     0      0         0    0      0    0                                     Corn                                                                            0            35        50   60     70   75                                    10     0      40        65   70     70   80                                    20     0      45        65   75     80   90                                    30     0      45        75   85     80   95                                    40     0      50        80   85     90   95                                    50     0      55        80   90     95   100                                   Corn grass                                                                      0            10        30   40     50   50                                    10     0      40        40   60     60   70                                    20     0      50        45   60     65   70                                    30     0      45        50   65     65   75                                    40     0      50        60   65     70   80                                    50     0      50        60   70     70   85                                    Lambsquarters                                                                   0            25        50   60     70   75                                    10      0     45        50   65     70   75                                    20     30     55        55   75     75   80                                    30     45     55        60   75     80   90                                    40     55     60        70   80     80   95                                    50     60     70        75   85     90   95                                    Italian ryegrass                                                                0            20        40   50     60   70                                    10     0      40        50   60     70   90                                    20     0      50        50   60     70   90                                    30     0      30        45   60     75   95                                    40     0      35        50   65     75   95                                    50     0      40        60   70     80   95                                    Sorell                                                                          0            60        80   80     90   100                                   10     0      70        80   90     90   100                                   20     0      70        80   90     90   100                                   30     0      75        85   95     100  100                                   40     20     75        90   95     100  100                                   50     60     80        100  100    100  100                                   Pigweed                                                                         0            30        40   55     75   90                                    10      0     40        50   60     80   90                                    20      0     65        70   65     80   90                                    30     20     65        75   80     85   100                                   40     30     70        80   90     90   100                                   50     40     70        80   90     95   100                                   Corn poppy                                                                      0             0        70   100    100  100                                   10      0     30        90   100    100  100                                   20      0     55        90   100    100  100                                   30     20     60        90   100    100  100                                   40     30     75        100  100    100  100                                   50     50     100       100  100    100  100                                   ______________________________________                                    

                  TABLE 5                                                          ______________________________________                                         Herbicidal action of composition 1.2                                           Plant mass in % of controls (+ denotes increase over controls)                 II\IB                                                                        0     2.5       5    10     25   50                                    ______________________________________                                         Wheat                                                                           0            +15       +20  +10    +10  +5                                     5     0      +10       +10  +5     +5   +10                                   10     0      +10       +15   0      0   +5                                    15     0       0        +10  +10     0    0                                    20     0       0         0    0      0    0                                    25     0       0         0    0      0    0                                    Corn                                                                            0     0      +10       +15  +10    +10  +20                                    5     0      +10       +10  +10    +20  +20                                   10     0      +10       +5   +10    +10  +10                                   15     0       0         0   +5     +5    0                                    20     0       0         0    0      0    0                                    25     0       0         0    0      0    0                                    Corn grass                                                                      0             0         0    0      0   30                                     5     0       0         0    0     10   40                                    10     0       0         0    0     15   40                                    15     0       0         0   10     15   30                                    20     0       0         0   10     20   35                                    25     0       0         0   10     20   40                                    Lambsquarters                                                                   0            30        50   80     90   90                                     5     0      40        65   85     95   95                                    10     30     70        75   90     95   100                                   15     45     75        80   90     100  100                                   20     55     75        80   90     100  100                                   25     60     80        90   95     100  100                                   Italian ryegrass                                                                0             0        10   20     25   40                                     5     0       0        20   20     30   40                                    10     0      30        35   40     45   65                                    15     0      35        40   40     50   70                                    20     0      40        45   40     50   70                                    25     0      40        45   40     60   70                                    Sorell                                                                          0             0         0   20     40   50                                     5     0       0        10   30     45   60                                    10     0      15        30   45     65   80                                    15     0      20        40   65     70   80                                    20     20     25        40   70     70   85                                    25     60     35        50   70     80   80                                    Pigweed                                                                         0            20        30   45     55   65                                     5     0      25        40   60     80   80                                    10     0      30        40   65     80   85                                    15     20     40        50   65     70   85                                    20     30     45        55   70     70   85                                    25     40     50        60   70     80   90                                    Corn poppy                                                                      0             0        20   30     45   60                                     5     0       0        45   55     75   100                                   10     0       0        50   60     80   100                                   15     20     30        60   70     80   100                                   20     30     40        65   70     85   100                                   25     50     45        70   80     85   100                                   ______________________________________                                    

                  TABLE 6                                                          ______________________________________                                         Herbicidal action of composition 1.3                                           Plant mass in % of controls (+ denotes increase over controls)                 0         3         6      9      15   21                                      ______________________________________                                         Wheat                                                                           0            +5        +10  +10    +10  +5                                    10     0      +10       +15  +20    +10   0                                    20     0       0        +10  +15    +10   0                                    30     0       0         0   +15    +15   0                                    40     0       0         0    0      0    0                                    50     0       0         0    0      0    0                                    Corn                                                                            0            +5        +10  +20    +10   0                                    10     0      +5        +10  +20    +20  +10                                   20     0      +10       +15  +20    +10  +10                                   30     0      +5        +10  +20    +10   0                                    40     0       0         0   +10     0    0                                    50     0       0         0    0      0    0                                    Corn grass                                                                      0            15        25   50     70   70                                    10     0      50        60   60     80   80                                    20     0      50        65   70     80   80                                    30     0      55        60   70     90   85                                    40     0      60        70   70     90   85                                    50     0      60        70   75     90   90                                    Lambsquarters                                                                   0            30        55   70     80   90                                    10     0      40        60   85     100  100                                   20     30     50        60   90     100  100                                   30     45     65        70   90     100  100                                   40     55     70        75   90     100  100                                   50     60     80        80   95     100  100                                   Italian ryegrass                                                                0            30        50   65     75   80                                    10     0      50        65   80     85   100                                   20     0      55        70   85     85   100                                   30     0      60        70   85     90   100                                   40     0      60        80   90     90   100                                   50     0      65        70   90     90   100                                   Sorell                                                                          0            50        80   90     95   100                                   10     0      75        90   100    100  100                                   20     0      80        90   100    100  100                                   30     0      80        90   100    100  100                                   40     20     90        95   100    100  100                                   50     60     95        100  100    100  100                                   Pigweed                                                                         0            40        50   55     80   90                                    10     0      50        55   50     80   100                                   20     0      65        60   70     80   100                                   30     20     70        75   80     90   100                                   40     30     70        80   80     90   100                                   50     40     75        85   90     100  100                                   Corn poppy                                                                      0            20        70   100    100  100                                   10     0      40        90   100    100  100                                   20     0      50        90   100    100  100                                   30     20     70        100  100    100  100                                   40     30     70        100  100    100  100                                   50     50     80        100  100    100  100                                   ______________________________________                                    

                                      TABLE 7                                      __________________________________________________________________________     Herbicidal action and synergy of composition 1.1 and mixture of                sulfonylureas (MX) with Dicamba                                                                  Dosage                                                                             Decrease in mass of plants  %!                                             g/ha of                                                                            Corn grass                                                                          Sorrell                                                                            Corn poppy                                      Composition       act. pr.                                                                           E    E   E                                               __________________________________________________________________________     IA                2.0 10   60  0                                               II                32.0                                                                               0    0   0                                               I.Ic              32.0                                                                               45/+35                                                                              75/+15                                                                             60/+40                                                                *)45/+35                                                                            70/+10                                                                             60/+40                                                                **)43/+33                                                                           70/+10                                                                             58/+38                                          MX(R.sub.1 = Cl) + Dicamba (1:15)                                                                32.0                                                                               40/+30                                                                              60/0                                                                               50/+30                                                                *)25/+15                                                                            40/-20                                                                             25/+5                                                                 **)18/+8                                                                            32/-28                                                                             20/0                                            ID                4.0 15   50  10                                              II                30.0                                                                                0    0  20                                              I.5a              32.0                                                                               50/+35                                                                              60/+10                                                                             65/+37                                                                *)55/+40                                                                            55/+5                                                                              65/+37                                                                **)48/+33                                                                           55/+5                                                                              60/+32                                          MX(R.sub.1 = OCH.sub.2 CH.sub.2 Cl) + Dicamba (1:15)                                             32.0                                                                               40/+25                                                                              50/0                                                                               45/+17                                                                *)20/+5                                                                             15/-35                                                                             30/-8                                           __________________________________________________________________________      *)The solution was kept 30 days prior to treatment                             **)The solution was kept 60 days prior to treatment                      

                  TABLE 8                                                          ______________________________________                                         Effects of the herbicidal compositions based on (IA) and (II)                  on weeds and crop yields of spring wheat                                                          Weeds          Crop  Increase                                          Dosage  decr.   E      yield in yield                               Example    g/ha    in %    %      cnt/ha                                                                               cnt/ha                                 ______________________________________                                         1.1e       25      60      -13    21.8  -0.7                                   1.1e       50      90       -7    22.9  0.4                                    1.1b       25      50       +4    22.8  0.3                                    1.1b       50      90       +8    26.1  3.6                                    1.1c       25      50      +22    26.7  4.2                                    1.1c       50      95      +31    30.0  7.5                                    1.1a       25      40      +10    23.7  1.2                                    1.1a       50      80      +16    25.5  3.0                                    controls                                                                       (IA)       10      95             25.4  2.9                                               5       70             23.1  0.6                                               2.5     40             23.5  1.0                                    (II)       150     70             25.6  3.1                                               50      40             22.5  0                                                 25      10             21.7  -0.8                                   manual weeding                                                                            --      100            25.3  2.3                                               --       0             22.5  --                                     ______________________________________                                    

MMDO₀.5 =3.2 cnt/ha

E--biological effect of the mixture:

(-)--antagonism

(+)--synergism

Calculated in % according to Colby equation:

    E=E.sub.o -E.sub.c

wherein

E_(o) --observed % of weeds destroyed by mixture

E_(c) --calculated % of weeds destroyed by mixture

    E.sub.o =X+Y-X.Y/100

X--% of weeds destroyed by herbicide (IA)

Y--% of weeds destroyed by herbicide (II)

                  TABLE 9                                                          ______________________________________                                         Effects of the herbicidal compositions based on (I) and (II)                   on weeds and crop yields of spring wheat                                                          Weeds          Crop  Increase                                         Dosage   decr.   E      yield in yield                               Example   g/ha     %       %      cnt/ha                                                                               cnt/ha                                 ______________________________________                                         1.1c      50       85/95   +27/+13                                                                               30.0  7.5                                    1.4a      50        90/100 +25/+15                                                                               28.7  6.2                                    1.5a      50       80/80   +29/+10                                                                               25.2  2.7                                    1.6a      50       60/80   +9/+1  25.6  3.1                                    IA        2.5      40/70          23.5  1.0                                    IC        2.5      50/70          23.9  1.4                                    ID        2.5      30/65          22.7  0.2                                    IF        2.5      30/50          24.1  1.6                                    II        50       30/40          22.5  0                                      manual weeding     100/100        25.3  2.8                                                       0              22.5  --                                     ______________________________________                                    

MMD₀.5 =3.1 cnt/ha

changes in weediness given as: number of weeds on m² /weed mass g/m²

                  TABLE 10                                                         ______________________________________                                         Effects of the herbicidal compositions based on (IB) and (II)                  on weeds and crop yields of corn                                                         Weeds, decrease in % of                                                                       Crop.   Increase                                              Dosage  mass             yield in yield                                Example g/ha    millet    pigweed  cnt/ha                                                                               cnt/ha                                ______________________________________                                         1.2b    60      30        60       217   20                                    1.2b    80      40        70       234   37                                    1.2b    120     40        75       223   26                                    1.2c    60      45        90       198    1                                    1.2c    80      65        95       245   48                                    1.2c    120     70        95       238   41                                    1.2d    60      50        70       226   39                                    1.2d    80      60        90       234   37                                    1.2d    120     75        90       218   21                                    controls                                                                       IB      50      15        60       231   34                                    II      150     30        70       221   24                                    no herbicide                                                                           --       0         0       197   --                                    ______________________________________                                    

MMD₀.5 =30 cnt/ha ##STR7## 

I claim:
 1. A herbicidal composition for use in cereals, comprising at least one benzenesulfonylurea derivative and at least one dichlorobenzoic acid derivative in synergistic herbicidally effective amounts, a surfactant, an organic solvent, and water, wherein the benzenesulfonylurea derivative is of the formula (I)wherein: R₁ is Cl; R₂ is H; R₃ is CH₃ ; R₄ is OCH₃ ; R₅ is C₂ H₅ ; and R₆ is C₂ H₅ ;and the derivative of dichlorobenzoic acid is a 2-methoxy-3,6-dichlorobenzoic acid of the formula (II) ##STR8## wherein: R₇ is CH₃ ; R₈ is CH₃ ; and R₉ is H;with the following weight percentages of compounds:

    ______________________________________                                         ammonium salt of benzenesulfonylurea derivative                                                           2.0-50                                              ammonium salt of 2-methoxy-3,6-dichlorobenzoic acid                                                       5.0-50                                              surfactant                 1.0-5.0                                             organic solvent            10-40                                               water                      up to
 100.                                          ______________________________________                                    


2. The herbicidal composition of claim 1, wherein the surfactant is selected from the group consisting of bis-polyoxyethylated alkylamine, sodium bis(2-ethylhexyl)succinate sulfonate, polyethyleneglycol monoalkyl ethers, and alkylaryl ethers of polyethyleneglycol or polypropyleneglycol.
 3. The herbicidal composition of claim 1, wherein the organic solvent is triethyleneglycol.
 4. A herbicidal composition for use in cereals, comprising synergistic herbicidally effective amounts of:2.0 weight percent of a benzenesulfonylurea derivative of formula (I) ##STR9## wherein: R₁ is Cl; R₂ is H; R₃ is CH₃ ; R₄ is OCH₃ ; R₅ is C₂ H₅ ; and R₆ is C₂ H₅ ; 40weight percent of an ammonium salt of 2-methoxy-3,6-dichlorobenzoic acid of formula (II) ##STR10## wherein: R₇ is CH₃ ; R₈ is CH₃ ; and R₉ is H;
 3. 0 weight percent of a surfactant selected from the group consisting of bis-polyoxyethylated alkylamine, sodium bis (2-ethylhexyl) succinate sulfonate, polyethyleneglycol monoalkyl ethers, and alkylaryl ethers of polyethyleneglycol or polypropyleneglycol;20 weight percent of triethylene glycol; and 35 weight percent of water.
 5. A method for control of undesired vegetation in cereals comprising treating an area under crops with a herbicidal composition comprising a derivative of benzenesulfonylurea and a derivative of dichlorobenzoic acid in synergistic herbicidally effective amounts, a surfactant, an organic solvent, and water, wherein the derivative of benzenesulfonylurea is of the formula (I) ##STR11## wherein: R₁ is Cl;R₂ is H; R₃ is CH₃ ; R₄ is OCH₃ ; R₅ is C₂ H₅ ; and R₆ is C₂ H₅ ;and the derivative of dichlorobenzoic acid is a 2-methoxy-3,6-dichlorobenzoic acid of the formula (II) ##STR12## wherein: R₇ is CH₃ ; R₈ is CH₃ ; and R₉ is H;with the following weight percentages of compounds:

    ______________________________________                                         ammonium salt of benzenesulfonylurea derivative                                                           2.0-50                                              ammonium salt of 2-methoxy-3,6-dichlorobenzoic acid                                                       5.0-50                                              surfactant                 1.0-5.0                                             organic solvent             10-40                                              water                      up to
 100.                                          ______________________________________                                    

with the application dosage of active principles being in the range of 25-125 g/ha. 